/**
 *
 */
package com.sihai.core.support;

import java.io.Serializable;
import java.lang.reflect.Method;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;

import org.hibernate.HibernateException;
import org.hibernate.type.NullableType;
import org.hibernate.type.TypeFactory;
import org.hibernate.usertype.ParameterizedType;
import org.hibernate.usertype.UserType;

/**
 * <p>
 * Hibernate UserType for jdk1.5 enum<br>
 * useage:
 *
 * <pre>
 * <code>
 *  &lt;typedef name=&quot;enum&quot; class=&quot;com.cctoo.framework.GenericEnumUserType&quot;&gt;
 *      &lt;param name=&quot;enumClass&quot;&gt;com.cctoo.crm.model.Role&lt;/param&gt;
 *      &lt;param name=&quot;identifierMethod&quot;&gt;name&lt;/param&gt;
 *      &lt;param name=&quot;valueOfMethod&quot;&gt;valueOf&lt;/param&gt;
 *  &lt;/tyepdef&gt;
 * </code>
 * </pre>
 *
 * by default.if will persist enum's name to database
 */
public class GenericEnumUserType implements UserType, ParameterizedType {

	private static final String DEFAULT_IDENTIFIER_METHOD_NAME = "name";

	private static final String DEFAULT_VALUE_OF_METHOD_NAME = "valueOf";

	@SuppressWarnings("rawtypes")
	private Class<? extends Enum> enumClass; //enum 类全名

	private Class<?> identifierType;

	private Method identifierMethod;

	private Method valueOfMethod;

	private NullableType type;

	private int[] sqlTypes;

	public void setParameterValues(Properties parameters) {
		String enumClassName = parameters.getProperty("enumClass");
		try {
			enumClass = Class.forName(enumClassName).asSubclass(Enum.class);
		} catch (ClassNotFoundException cfne) {
			throw new HibernateException("Enum class not found", cfne);
		}

		String identifierMethodName = parameters.getProperty("identifierMethod", DEFAULT_IDENTIFIER_METHOD_NAME);

		try {
			identifierMethod = enumClass.getMethod(identifierMethodName, new Class[0]);
			identifierType = identifierMethod.getReturnType();
		} catch (Exception e) {
			throw new HibernateException("Failed to obtain identifier method", e);
		}

		type = (NullableType) TypeFactory.basic(identifierType.getName());

		if (type == null)
			throw new HibernateException("Unsupported identifier type " + identifierType.getName());

		sqlTypes = new int[] { type.sqlType() };

		String valueOfMethodName = parameters.getProperty("valueOfMethod", DEFAULT_VALUE_OF_METHOD_NAME);

		try {
			valueOfMethod = enumClass.getMethod(valueOfMethodName, new Class[] { identifierType });
		} catch (Exception e) {
			throw new HibernateException("Failed to obtain valueOf method", e);
		}

	}

	@SuppressWarnings("rawtypes")
	public Class returnedClass() {
		return enumClass;
	}

	public Object nullSafeGet(ResultSet rs, String[] names, Object owner) throws HibernateException, SQLException {
		if (rs.getObject(names[0]) == null)
			return null;
		Object identifier = type.get(rs, names[0]);
		if (identifier == null) {
			return null;
		}

		try {
			return valueOfMethod.invoke(enumClass, new Object[] { identifier });
		} catch (Exception e) {
			throw new HibernateException("Exception while invoking valueOf method '" + valueOfMethod.getName()
					+ "' of " + "enumeration class '" + enumClass + "'", e);
		}
	}

	public void nullSafeSet(PreparedStatement st, Object value, int index) throws HibernateException, SQLException {
		try {
			if (value == null) {
				st.setNull(index, type.sqlType());
			} else {
				Object identifier = identifierMethod.invoke(value, new Object[0]);
				type.set(st, identifier, index);
			}
		} catch (Exception e) {
			throw new HibernateException("Exception while invoking identifierMethod '" + identifierMethod.getName()
					+ "' of " + "enumeration class '" + enumClass + "'", e);
		}
	}

	public int[] sqlTypes() {
		return sqlTypes;
	}

	public Object assemble(Serializable cached, Object owner) throws HibernateException {
		return cached;
	}

	public Object deepCopy(Object value) throws HibernateException {
		return value;
	}

	public Serializable disassemble(Object value) throws HibernateException {
		return (Serializable) value;
	}

	public boolean equals(Object x, Object y) throws HibernateException {
		return x == y;
	}

	public int hashCode(Object x) throws HibernateException {
		return x.hashCode();
	}

	public boolean isMutable() {
		return false;
	}

	public Object replace(Object original, Object target, Object owner) throws HibernateException {
		return original;
	}

}
